Variable-speed gear.



-M. A. OCONNOR. VARIABLE SPEED GEAR. APPLICATION FILED JUNE 20' 1910-1,14%,951 o I Patented June 8,1915.

2 SHEETSSHEET l- M. A. OCONNOR.

VARIABLE smo GEAR.

. APPLICATION FILED JUNE 20-1910, I 7

1 12 51 9 PamntedJ Mae-'8, 191.5.

2 SHKETS-SHEET 2.

AT'TU HN EY iii'ivrrnn sirnrns retainer oi rion MARTIN A. OFGONNOR, OFPROVIDENQE, RHODE ISLAND, ASSIGNOR TO PROVIDENCE IBLGVJER COMPANY, OFPROVIDENCE, RHODE ISLAND, A CORPORATION OF RHODE- ISLAND.

VARIABLE-SPEED (HEAR.

Specification of Letters Patent.

Patented June 8, $915.

Application filed June 20, 1910. Serial No. 567,790.

To all whom it may concern Be it known that I, MARTIN A. OCoNNoR, of thecity and county of Providence and State of Rhode Island, have inventedcertain new and useful Improvements in Variable- Speed Gears; and I dohereby declare the following specification, taken in connection with theaccompanying drawings, forming it part of the same, tobe a full clear,and eX- cct description. thereof.

My invention relates to improvements in variable speedgeors and isparticularly designed and adapted for use in connection with my improvedblower shown in my Pctout No. 951,197, dated March 8, 1910, but it isalso useful in other devices Where c variable speed is desired.

, The variable speed gears now in use, the most common of which are theelliptical gears, have certain objectionable features. In the firstplace with elliptic-cl gears the work is not performed at a constantrate and there is a variable load upon the driving shaft. Furthermore,in the use of elliptical gears the Work of acceleration is so variableand irregular that if the momentum is made great enough to keep thedriven gear in contact with the driving gear at the point where theretardation is most rapid, the strain on the mechanism is so great as tocause excessive friction and liability of damage. In elliptical gearsalso the line of action of the teeth at certain points, especiallyduring retardution of the driven gear, is very disadvanta-geous.

It is the object of my invention to obviate these objectionablefeatures, and to this end the invention consists in providing a pair ofvariable speed gears which will perform the work at a constant rate,thereby placing a constant load upon the driving shaft.

It further consists in providing a pair of variable speed gears whichwill give both a constant and variable speed to the driven shaft.

It further consists in providing a pair of variable speed ears, theconstruction and operation of whlch is such that the work ofacceleration can be accomplished while the work or load is light and ata rate which will make the total load upon the driving shaft constant.

It further consists in providing a pair of variable speed gears whichare so constructed and arranged that onecf said gears will make anypredetermined number of revolutions while the other gear is making onerevolution.

It further consists in the novel construction and arrangement of gearshereinafter described and more specifically set forth in the claims.

in describing the invention in detail reference will. be made to theaccompanying drawings in which-- Figure 1 is a plan face view of mynovel variable speed gears showing the some in nesh. Fig. 2 is nvsimilarview of it modification.

Refer-ring to the drawings, A represents thedriving gear and B thedriven gear. T he driving gear A is provided with two concentric toothedarcs 1 and 2, respectively, of different ,rcdii which are arranged andadapted t6 'lllQSll with two counterpart toothed arcs 1 and 2.,respectively, on the driven gear B. The teeth on the concentric portions1,2, 1, and 2 may be of the standard involute or epicycloidcl form or ofany other desired form practical for spur gears. Connecting thetwo'concentric toothed arcs l and 2 on the driving goal A are two eccentrio toothed arcs 8 and 4, respectively. The teeth on the eccentric arcs3 ,and 4: are carnshaped and gradually increase in size, the smallestradius ahd the largest tooth being adjacent the concentric are havingthe smallest radius. Connecting the two concentric toothed arcs 1 and 2on the driven gear B are two counterpart eccentric toothed arcs 1 3' andl, respectively. The teeth onthe' ECGBHEMC arcs 3 and e arecani-shaped'and gradually decrease, the largest tooth being adjacent theconcentric are having the greatest radius and the smallest tooth beingadjacent the concentric are having the smallest radius.

The cam-shaped teeth on the eccentric portions 8, l, 3 and 4t aredesigned to give the desired acceleration and retardation to I thedriven gear B. As shown in the drawings, the cum-shaped teeth on thedriven gear B are formed with'a straight radial face 5 and thecooperating camsheped teeth on the driving gear A are formed with aslightly curved face 5. With this construction a very strong tooth isproduced and the line of action on the driven gear will. beperpendicular to the radius thereof, and on the driving gear very nearlyso, which results in a very eiiicient form of tooth.

With the above described form of gears, ii the driving gear A is drivenat a constant rate in the direction of'its arrow,.the driven gear B willbe driven at a slow constant speed in the direction of its arrow, whilethe arcs 1 and 1 are in mesh; will be accelerated while the arcs 3' and3 are in mesh; will be driven at a high constant speed while the arcs 2and '2 are in mesh; and will be retarded while the arcs 4: and 4 are inmesh. As there are two sets of arcs 1', 2, 3', and 4: on the driven gearB, it will take two revolutions of the driving gear A to produce onerevolution of the driven gear B and there will be two constant-low speedperiods,

I two constant high speed periods, two periods of acceleration, and twoperiods of retardation in each revolutionof the driven gear.

It will be seen that during the period of retardation the cam-shapedteeth on. the

driving gear tend to move away from and out of mesh with thecorresponding canishaped teeth on the "driven gear. The inertia of thedriven gear and its accessories, however, tendto keep said driving gearturning at a constant rate, and if the re tarding action of the drivinggear is greater than the retarding efiect of the Work imposed on thedriven gear, and this is arranged for in the design of the cam-shapedteeth, the driven gear, by reason of its greater momentum, becomes forthe time being the driving gear and its cam-shaped teeth remain in closecontact with the corresponding teeth on the driving gear until the teethon the concentric arcs of said gears come into mesh. If, however, thegears as above described should stop at a point when the. driven gear isbeing retarded, then it would be impossible to again start the gears byreason of the fact that there-would be no momentum to hold thecam-shaped teeth on the driven gear in engagement with the correspondingteeth on the driving gear and said gears would go out of'inesh. To

. obviate this objectionable feature I provide the driving gear A with acam-plate 6 secured to the race thereof and the driven gear B with acircular cam-plate 6 secured to its face, as shown in'Fig. 2. Thecam-plate 6 is provided with two oppositely disposed cams 7 and 8 whichare constructed and arranged to cooperate with a series of cams 7, 8,and 8 formed on the periphery of the cam-plate 6. With this constructionwhen the driven gear is being retarded the cam'face of cam 7 will engagewith the camface of cam 7, and if there is any tendency for the drivengear to lag behind that driver, said cams will act to revolve saiddriven 'mesh during the period of retardation. The

second set of cams 8 and 8 are provided to act when it is desired toreverse the rotation of the gears.

With my improved form of gears it will be seen that the driving gearwill rotate twice while the driven gear is rotating once, and if desiredthe concentric arcs and the eccentric arcs may be increased in number onthe driven gear so that three revolutions of the driving gear will benecessary to cause one revolution of the driven gear and there will thenbe three constant high speeds, three constant low speeds, threeaccelerations, and three retardatlons at each revolution of the drivengear. It will of course be understood that the gears may be reversed andthe gear A be made the driven gear and the gearB the driving gear. a

What I claim as my invention and desire to secure by Letters Patent is:

1. A variable speed gear having a concentric toothed arc and aneccentric toothed are upon the periphery thereof.'

2. A variable speed gear having a series of concentric toothed arcs anda series of eccentric toothed arcs, the teeth .on the ecsaid eccentrictoothed arcs being cam-shaped .and of varyin size.

4:. A pair or variable speed gears comprising a driving gear and adriven gear, said gears being provided upon the periphery thereof withmeans whereby the driving gear will drive the driven gear at bothconstant and variable speeds.

5. A pair of variable spcedgears comprising'a driving gear and a drivengear, each of said gears having a high speed cbncentric toothed are, alow speed concentric toothed are, an eccentric toothed are arranged andadapted to accelerate the speed-of the driven gear, and an eccentrictoothed are arranged and adapted to retard the speed of said drivengear. c a

6. A pair of variable speed gears comprising a driving gear and a drivengear, each of said gears having a high speed concentric toothed are, alow speed concentric toothed are, an eccentric toothed are foraccelerating the speed of the driven gear, an eccentric toothed are forretarding the speed of the driven gear, and means coiiperating with eachother to drive the driven gear during the retarding eriod.

7 A pair 0 variable speed gears comprising a driving gear and a drivengear, said gears being provided with means for rotating said driven gearat both constant and variable speeds, and separate means for drivingsaid driven gear during the variable speed.

8. o A pair of variable speed gears comprising a driving gear anda'driven gear, said gears being provided with incans for rotating thedriven gear at a number of different constant speeds, a number of speedsof acceleration, and a number of speeds of retardation, and. means fordriving the driven gear during the periods ofre'tardation.

9. A pair of variable speed gears comprising a driving gear and a drivengear, said driving gear being provided with two concentric toothed arcs,two eccentric toothed arcs and a cam overlying one of the eccentrioarcs, and said driven gear being pro vided with a series of concentrictoothed arcs, a series of eccentric toothed arcs, and a series of camsoverlying said eccentric arcs and adapted to be engaged by and cooperatewith the cam overlying the eccentric are on the driving gear.

10. A pair of variable speed gears com prising a driving gear and adriven gear, said driving gear being provided with two concentrictoothed arcs, two ecceniric toothed i.

arcs and a cam-plate secured to one fees thereof and having two cams,one of cams overlying one of said eccentric srcs overlying saideccentric arcs and edagpted to be engaged by and cooperate with the camsoverlying the eccentric arcs on the driving gear.

i MARTIN A. UCQNNQE;

Witnesses Pi. H. Trinnsroivl J. H. Tr-rURsroN.

'a lid driven,

